Increasingly more electronic apparatuses include a touch screen, which makes it convenient to operate the electronic apparatuses. However, a user may inadvertently touch a screen key displayed on the touch screen to execute a specific function. To prevent the inadvertent operation, the electronic apparatuses typically include a screen lock mode. When it is unnecessary to operate the electronic apparatuses, the user may manually set the electronic apparatuses to a screen lock state, thereby locking an input function of the touch screen. The screen lock state may also be automatically activated when the electronic apparatuses remain in a non-operation state for a certain period of time. In order to use the touch screen to execute a function again, the user will have to unlock the screen.